In the specification, “a portable game machine” includes a portable multifunction terminal having functions, such as a portable phone terminal, and a portable music/image reproduction terminal, through which a game can be also enjoyed, in addition to a machine dedicated for games.
The portable game machine has such a strong inclination that a touch panel type of input portion using a screen of the display is used rather than a keyboard type in order to obtain the display having the broadest display area. As a general instance of the touch panel, the touch panel disclosed in a first prior art is known.